Friday, 24 April 2015

#Calbuco #Volcano Erupts

On April 22, 2015, Calbuco volcano in southern Chile began erupting
for the first time since 1972. An ash cloud rose at least 15 kilometers
(50,000 feet) above the volcano, menacing the nearby communities of
Puerto Montt (Chile) and San Carlos de Bariloche (Argentina). The
eruption led the Chilean Emergency Management Agency and the Chilean
Geology and Mining Service (SERNAGEOMIN) to order evacuations within a
20-kilometer (12 mile) radius around the volcano. About 1,500 to 2,000
people were evacuated; no casualties have been reported so far.

The volcanic mountain was quiet until tremors began late in the afternoon on April 22. An explosive pyroclastic
eruption started at 6:04 p.m. local time (2104 Universal Time) and
vigorously spewed ash and pumice for at least 90 minutes. Lava flows
were observed from the main vent. A second high-energy pulse of ash
occurred around 1 a.m. on April 23, according to SERNAGEOMIN.

At 11:20 a.m. local time (1420 Universal Time) on April 23, the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra
satellite acquired a natural-color image of the extensive ash plume
(top). Four hours later, at 3:35 p.m. local time (1835 Universal Time),
the MODIS instrument on NASA’s Aqua
satellite acquired a second view (bottom) as the tan plume continued
moving north and east. Note that the second image is at a wider scale
than the first.

Satellite instruments also acquired unusual nighttime views of the
eruption (below) in the early morning hours of April 23. The joint
NOAA/NASA Suomi NPP satellite observed atmospheric waves above Calbuco and its plume. The first image from the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP shows the heat signature of the hot ash in longwave infrared (11.45 micrometer channel).

The second image shows the same area as observed by the VIIRS day-night band
(DNB), which detects faint light signals such as city lights,
moonlight, and auroras. In this case, the DNB detected faint concentric
ripples in the mesosphere; they are made visible by airglow—faint
light emitted at night when atmospheric gases release energy that they
absorbed from sunlight during the day—which the DNB can detect. These
ripples are atmospheric gravity waves caused by the shock from the
eruption.

Click here to see a time-lapse video of the initial eruption from the ground.

The first and second images are by Joshua Stevens, NASA Earth Observatory, and Jeff Schmaltz, LANCE/EOSDIS Rapid Response at NASA Goddard. The third and fourth images are by Jesse Allen, NASA Earth Observatory, using VIIRS data from the Suomi National Polar-orbiting Partnership.
Caption by Mike Carlowicz. Special thanks to William Straka of the
University of Wisconsin’s Cooperative Institute for Meteorological
Satellite Studies (CIMSS).